The Container driver provides a lightweight solution for share
servers management. It allows to use Docker containers for hosting
userspace shared file systems services.

Supported operations

• Create CIFS share;
• Delete CIFS share;
• Allow user access to CIFS share;
• Deny user access to CIFS share;
• Extend CIFS share.

Restrictions

• Current implementation has been tested only on Ubuntu. Devstack
  plugin won’t work on other distributions however it should be possible
  to install prerequisites and set the driver up manually;
• The only supported protocol is CIFS;
• The following features are not implemented:
  • Manage/unmanage share;
  • Shrink share;
  • Create/delete snapshots;
  • Create a share from a snapshot;
  • Manage/unmanage snapshots.

Known problems

• May demonstrate unstable behaviour when running concurrently. It is
  strongly suggested that the driver should be used with extreme care in
  cases other than building lightweight development and testing
  environments.

Setting up container
driver with devstack

The driver could be set up via devstack. This requires the following
update to local.conf:

enable_plugin manila https://opendev.org/openstack/manila <ref>
MANILA_ENABLED_BACKENDS=london
MANILA_OPTGROUP_london_driver_handles_share_servers=True
MANILA_OPTGROUP_london_neutron_host_id=<hostname>
SHARE_DRIVER=manila.share.drivers.container.driver.ContainerShareDriver
SHARE_BACKING_FILE_SIZE=<backing file size>
MANILA_DEFAULT_SHARE_TYPE_EXTRA_SPECS='snapshot_support=false'

where <ref> is change reference, which could be copied from
gerrit web-interface, <hostname> is the name of the host with
running neutron

Setting Container Driver
Up Manually

This section describes steps needed to be performed to set the driver
up manually. The driver has been tested on Ubuntu 14.04, thus in case of
any other distribution package names might differ. The following
packages must be installed:

• docker.io

One can verify if the package is installed by issuing
sudo docker info command. In case of normal operation it
should return docker usage statistics. In case it fails complaining on
inaccessible socket try installing apparmor. Please note
that docker usage requires superuser privileges.

After docker is successfully installed a docker image containing
necessary packages must be provided. Currently such image could be
downloaded from https://github.com/a-ovchinnikov/manila-image-elements-lxd-images/releases/download/0.1.0/manila-docker-container.tar.gz
The image has to be unpacked but not untarred. This could be achieved by
running ‘gzip -d <imagename>’ command. Resulting tar-archive of
the image could be uploaded to docker via

sudo docker load --input <imagename.tar>

If the previous command finished successfully you will be able to see
the image in the image list:

sudo docker images

The driver expects to find a folder /tmp/shares on the host where it
is running as well as a logical volume group
“manila_docker_volumes”.

When installing the driver manually one must make sure that ‘brctl’
and ‘docker’ commands are present in the
/etc/manila/rootwrap.d/share.filters and could be executed as root.

Finally to use the driver one must add a backend to the config file
containing the following settings:

driver_handles_share_servers = True
share_driver = manila.share.drivers.container.driver.ContainerShareDriver
neutron_host_id = <hostname>

where <hostname> is the name of the host running neutron. (In
case of single VM devstack it is VM’s name).

After restarting manila services you should be able to use the
driver.